The introduction

 The example describes how to create the grid which has three levels :

1. Flight direction (Departure/Arrival city) ;

2. Airline/ Flight Connection Number ; 

3. An information about flights per day .

The example is based on data of standard demo-tables SPFLI / SFLIGHT :

First level of list: Departure/Arrival city

Second level of list: Airline/ Flight Connection Number

Third level of list: Flights per day